At least two different monomers can be polymerized in the same polymerization system so as to generate a copolymer having those different monomer units arranged as repeating units in one polymer chain, and the copolymer thus obtained can be classified into a random copolymer, an alternating copolymer, a block copolymer, or a graft copolymer, depending on the arrangement of the monomer units. However, no report has been made on the arrangement of monomer units in polymerization reaction of a conjugated diene compound and a non-conjugated olefin.
For example, JP 2000-154210 A (PTL 1) discloses a catalyst for polymerization of a conjugated diene, the catalyst including a group IV transition metal compound which has a cyclopentadiene ring structure, in which an α-olefin such as ethylene is exemplified as a monomer copolymerizable with the conjugated diene. However, no reference is made on the arrangement of monomer units in the copolymer. Further, JP 2006-249442 A (PTL 2) discloses a copolymer of an α-olefin and a conjugated diene compound, but no reference is made on the arrangement of monomer units in the copolymer. Further, JP 2006-503141 A (PTL 3) discloses an ethylene/butadiene copolymer synthesized by using a catalytic system consisting of a specific organometallic complex, but merely describes that the butadiene as a monomer is inserted in the form of trans-1,2-cyclohexane into the copolymer, without making any reference to the arrangement of monomer units in the copolymer, and no reference is made to a rubber manufactured by using a block copolymer in which a cis bond content or a vinyl bond content (content of 1,2 adducts (including 3,4 adducts)) is defined so as to obtain high elasticity modulus, an excellent low heat generating property, crack growth resistance, and ozone resistance.
In addition, JP 11-228743 A (PTL 4) discloses an unsaturated elastomer composition composed of an unsaturated olefin-based copolymer and a rubber, but merely describes that monomer units in the copolymer are randomly arranged and makes no reference to a block copolymer in which a cis bond content or a vinyl bond content (content of 1,2 adducts (including 3,4 adducts)) is defined so as to be able to manufacture a rubber that has high elasticity modulus, an excellent low heat generating property, an excellent crack growth resistance, and an excellent ozone resistance.
Further, JP 2000-86857 A (PTL 5) discloses a butadiene copolymer having: a vinyl content (vinyl bond content, 1,2 adduct (including 3,4 adduct) content) of 6%; a cis content of 92%, and an ethylene content of 3% or 9%. However, JP 2000-86857 A (PTL 5) does not describe or suggest a block copolymer in which a cis bond content or a vinyl bond content (content of 1,2 adducts (including 3,4 adducts)) is defined so as to be able to manufacture a rubber that has high elasticity modulus, an excellent low heat generating property, an excellent crack growth resistance, and an excellent ozone resistance.